The windows of buildings, show windows, sunroofs, roofs, walls, and the like, as well as the windows and bodies of automobiles, trains, and the like are exposed to sunlight, and therefore, particularly in summer, the interior temperature increases, and the comfortableness worsens. Therefore, measures are promoted in which a material for shielding sunlight, particularly near-infrared rays, is applied to a member, such as a window of a building, to shield near-infrared rays to suppress an increase in interior temperature and improve comfortableness. In order to apply a near-infrared shielding material to a member, such as a window of a building, a coating agent comprising the near-infrared shielding material is applied to the surface of glass, ceramic, or plastic that is the raw material of the member when the glass, ceramic, or plastic is manufactured or molded. Further, a coating agent comprising the near-infrared shielding material is applied to the surface of the member at a place where it is used, on the window or the like.
As such a near-infrared shielding material, oxide materials, such as tin oxide, antimony-doped tin oxide, indium oxide, tin-doped indium oxide, zinc oxide, aluminum-doped zinc oxide, lanthanum boride, cerium oxide, ruthenium oxide, and tungsten oxide, are known. In addition, metal materials, such as silver, copper, and aluminum, are also known.
As a binder component mixed in the coating agent, for example, Patent Literature 1 describes alkoxysilanes represented by Si(OR)mRn, wherein m+n=4, m=1 to 4, n=0 to 3, and R=a C1 to C4 alkyl group, or polymers thereof or partial hydrolysates thereof, and describes manufacturing a heat reflecting coating by applying the coating agent and then heating it. In addition, Patent Literature 2 describes a mixture of alkoxysilanes represented by the average composition formula (CH3)mSi(OR)4−m, wherein R is a methyl group or an ethyl group, and m=0.2 to 0.95, a hydrolysate of the above mixture, and a polycondensate of the above mixture, and describes applying the composition on the surface of a glass substrate, semi-curing the composition at a temperature of 200° C. or less, further applying a composition comprising a polysilazane compound thereon, and then performing heat treatment at a temperature of 400° C. or more and 750° C. or less to manufacture glass with an infrared shielding coating.
In addition, Patent Literature 3 describes a polymer substance obtained by reacting a silane compound comprising an amino group with a boron compound, and also describes further adding an alkoxysilane, such as tetramethoxysilane or tetraethoxysilane, or a polycondensate thereof. In addition, Patent Literature 4 describes that when a substance obtained by mixing and reacting a glycidoxypropyl group-containing alkoxysilane and an aminopropyl group-containing alkoxysilane is used, curing is possible at ordinary temperatures.